1. Field of Invention
The present invention comprises a teatcup comprising a shell, a tubular teatcup liner extending in the shell, and a valve housing having a connection pipe connectable to an end of the teatcup liner, the valve housing being arranged to be mounted to the shell and the connection pipe being arranged to be inserted into said end of the tubular teatcup liner, the valve housing and the shell comprising locking members arranged to engage each other disconnectably during said mounting in order to lock the valve housing to the shell.
2. Description of the Prior Art
A known milking machine comprises a number of teatcups to be applied to a respective teat of an animal to be milked. Usually, such a teatcup comprises an outer rigid shell and a tubular teatcup liner extending in the shell. When the teatcup is applied to a teat of an animal to be milked, the inner wall of the tubular teatcup liner will thus abut the teat. Since the teatcup liners shall provide a pulsating pressure against the teat they must be elastic. Every elastic material, at least such which are available today, is subjected to a deterioration of the elastic capacity over the time and by use. Although the shell of the teatcup has a very long lifetime, the teatcup liners are thus an article of consumption which has to be replaced within equal time intervalls. Thereby, a teatcup liner to be replaced has to be removed from the shell of the teatcup and a new teatcup liner has to be mounted in the shell. Teatcups known do not function in a satisfactorily manner in this respect and this operation of replacement is difficult and time consuming. In addition, it happens that the teatcup liner is not always mounted in a proper position in the shell, which means that the teatcup will not function in a optimal manner during the milking operation.
With regard to teatcups for milking of in the first place smaller animals, such as sheep, goats etc., having merely two teats, there is normally no claw for collecting the milk from the different teatcups before the milk is conducted further to a milk receiving member of the milking machine but instead the milk is conducted from each teatcup directly to the milk receiving member of the milking machine. This means, that a valve housing having a closing valve, closing the milk conduit and preventing air rush when the teatcup is not attached to a teat, has to be provided in connection to each teatcup.
IT-A-1 202 068 discloses a teatcup intended for milking of goats and sheep and comprising a shell, a tubular teatcup liner extending in the shell and valve housing having a connection pipe connectable to one end of the teatcup liner. The lower end of the teatcup liner extends out of the shell and is adapted to receive the connection pipe of the valve housing therein. The teatcup lacks any connection members between the valve housing and the shell, but instead the connection therebetween is provided merely by means of the application of the teatcup liner onto the connection pipe of the valve housing. In order to make such a connection sufficiently strong the lower end of the teatcup liner has to be pressed against the outer surface of the connection pipe by a relatively strong elastic force. By such a mounting method it is difficult to demount and once again mount the valve housing to the other parts. In addition, there is a great risk that the lower end of the teatcup liner will jam to the connection pipe over time due to the milk substances penetrating the joint therebetween. A further disadvantage of this teatcup is the relatively long height which, especially during milking of smaller animals having a small distance between the ground and the teats, may render the application of the teatcups more difficult and obstruct a free milk flow. This document also discloses a membrane controlled closing valve in the valve housing. Moreover, this valve comprises a cam member manually rotatable in order to ensure forcibly that it is kept in the open position.
EP-B-88 580 discloses a similar teatcup having a shell and a teatcup liner provided in the shell and having a lower end extending out from the shell and being configured in such a manner that it forms a valve housing. Thus, since the valve housing is an integrated part of the teatcup liner this has a rather complicated configuration which is not desirable in view of the fact that the teatcup liner is an article of consumption.
U.S. Pat. No. 2,986,117 discloses another teatcup having a shell and a teatcup liner extending in the shell and having a lower end bent outwardly around the outer surface of the shell. The teatcup has no locking member between the shell and the valve housing, but instead the shell with the teatcup liner provided thereon is inserted in a tubular upper end of a valve housing being manufactured in a transparent material and in such a manner that the shell and the teatcup liner are clamped in the valve housing. Thus, the teatcup liner will be clamped between the shell and the valve housing. Such a construction requires, in order to be reliable, a large elastic clamping force between the different parts, which, however, results in a difficult mounting and demounting of the parts. By such a construction there is also a great risk that the teatcup liner is turned during the mounting, which may result in folds on the teatcup liner and thus to a deteriorated function thereof.
GB-A-737 834 discloses a similar teatcup having a shell and a teatcup liner extending in the shell and having a lower end being bent outwardly around the outer surface of the shell. The shell and the teatcup liner so provided are inserted in a tubular upper end of a valve housing and in such a manner that the shell and the teatcup liner are clamped in the valve housing.
EP-A-645 079 discloses a teatcup as initially defined. The valve housing comprises a connection pipe which is inserted into a tubular lower end of the teatcup liner. It appears that the valve housing is connected to the shell by means of a thread connection. Thus it is necessary to rotate the valve housing in relation to the shell for mounting the teatcup. This means that there is a great risk that the teatcup liner will be twisted during the mounting process. Such twisting may lead to folds on the teatcup liner and consequently a proper function of the teatcup may not be guaranteed.